Many types of metal working equipment (lathes, mills, saws, cnc maching centers) use coolant to flood the work piece and the cutting tools to extend the life of the cutting tools, remove chips, and keep the machines from rusting. The coolant in a machine is obtained by taking a coolant concentrate and mixing it with water at a percentage that typically ranges from 2-10% coolant to water. The specific concentration is a function of the type of coolant concentrate, and the specific machine requirements.
Typically, the coolant in the machines need to be topped up every 6-8 hours of operation because of evaporation and that some of the coolant gets dragged out with the chips.
Maintaining correct coolant concentration and coolant level in a machine can be essential to part quality (maintaining tolerances and surface finishes) and tool life. This can be a labour intensive process, where buckets of coolant are carried to machines to top them up on a daily basis.